For many New Yorkers, riding the subway is an underground experience, calling to mind dark tunnels and fluorescent-lit stations. But the blizzard over the weekend was a reminder of just how much of the system runs aboveground.

With the announcement on Saturday that all of the outdoor stretches of the subway would close, huge swaths of the system suddenly disappeared from the map, primarily in the Bronx, Brooklyn and Queens.

It was the first time the Metropolitan Transportation Authority halted service to all of the aboveground stations while maintaining service to almost all underground stations. Altogether, 196 stations were closed, about 40 percent of the subway’s 469 stations, the authority said.

On Saturday afternoon, several hours into the storm, Gov. Andrew M. Cuomo announced the closings, saying that outdoor routes were having problems with equipment and icing. Kevin Ortiz, a spokesman for the transportation authority, said the decision was made by the agency after officials consulted with Mr. Cuomo.

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An M.T.A. worker on Saturday inspected the snow on the tracks near the Broadway Junction station in Brooklyn.CreditVictor J. Blue for The New York Times

Last winter, as a storm descended on New York City, the authority shut down the entire subway system, the first time it had taken such action for a snowstorm. But the agency did not consult with City Hall, and that snub of Mayor Bill de Blasio, coupled with the storm’s modest impact, led to criticism of the agency and Mr. Cuomo.

Since then, the authority had been preparing plans for how to offer partial service during a storm like the one over the weekend that covered Central Park with more than 26 inches of snow, the second-largest snowfall on record in the city.

“It’s a plan we worked on over the past year in order to provide service where we could, and we will continue to fine-tune it,” Mr. Ortiz said. “We’ll look at how things worked during the storm and adjust it accordingly.”

As the full subway map began to come back to life on Sunday morning, transit advocates praised the decision to maintain underground service during the storm. The move also got a stamp of approval from Mr. de Blasio, who had bristled at how the closing was handled last year.

As the storm intensified, many transit systems across the Northeast opted to close altogether, including New Jersey Transit and the Washington-area Metro. The Long Island Rail Road and Metro-North Railroad, which are part of the Metropolitan Transportation Authority, closed at 4 p.m. on Saturday, the same time that outdoor subway service was halted.

On New York City’s subway system, where lines often run both above and below ground, the authority did not simply halt the trains where they reach daylight. Officials ended service at stations where they had the necessary equipment to turn trains around to send them back in the other direction.

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Snowflakes started falling at Central Park on Friday night, forming a smooth white blanket that by Sunday would wrap the area in the pristine quiet of winter.

On the F line in Brooklyn, for instance, that meant stopping service at the Jay Street-MetroTech station, which had the proper switches to allow a train to move from one track to the other, instead of at Carroll Street, the last underground station before trains travel outdoors on the elevated Culver Viaduct.

A snowstorm in 2010 that left some riders stranded for hours changed the authority’s approach. Its chairman, Thomas F. Prendergast, said that episode was on his mind when he recommended shutting the system down last January.

John Raskin, executive director of the Riders Alliance, an advocacy group for subway and bus riders, called the authority’s decision to keep underground service running “smart and creative.”

“Nobody wants their service to be shut down,” Mr. Raskin said. “What people want even less is to be stranded because of ice on the rail.”

But with bus service shut down as well on Saturday, the closings had a bigger impact on low-income residents, many of whom live on the edges of the city. Manhattanites may not realize how much of the subway is aboveground, or how many people rely on buses, Mr. Raskin said.

“A blizzard has the effect,” he said, “of exacerbating social and geographical divisions in New York.”

A version of this article appears in print on , on Page A14 of the New York edition with the headline: Shutting Down Aboveground Subway Service, and Learning From Previous Missteps . Order Reprints | Today’s Paper | Subscribe